Bermudagrass hybrid named &#34;Ozarka&#34;

ABSTRACT

The variety “Ozarka” is a new and distinct hybrid bermudagrass variety. The plant was derived from an F1 hybrid cross of bermudagrass varieties A9959×“Coastal.” “Ozarka” has relatively tall, upright growth and exhibits superior cold tolerance relative to previous bermudgrass varieties, yielding well in the northern part of the bermudagrass belt.

BACKGROUND OF THE INVENTION

[0001] The invention relates generally to the new and distinct variety of hybrid bermudagrass (Cynodon dactylon (L.) Pers.) described herein and designated “Ozarka.” The variety was derived from an F1 hybrid cross of A9959×“Coastal” carried out in 1974 at the Oklahoma Agricultural Experimental Station, Oklahoma State University. “Ozarka” has been asexually reproduced and the distinctive traits of the variety have remained stable.

[0002] Parent line A9959 is a bermudagrass introduction from Yugoslavia. The Georgia Coastal Plain Experiment Station and Plant Science Research Division of ARS released Coastal in 1943. Coastal is the F1 hybrid of “Tift” bermudagrass and a plant introduction from South Africa.

[0003] “Ozarka” was selected from other bermudagrasses and evaluated for traits and characteristics as described herein. Initial field screenings identified “Ozarka” as having desirable characteristics. This led to its inclusion in advanced multi-environmental performance tests. The results of certain of the analyses are presented herein below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004]FIG. 1: “Ozarka” bermudagrass fully established and ready for harvest. Note: complete ground cover at least 18 months after sprigging.

[0005]FIG. 2: Individual plant of “Ozarka” bermudagrass. Note: Stoloniferious reproduction from main plant.

[0006]FIG. 3: Collar region of “Ozarka” bermudagrass. Note: small pubescence where the leaf sheath and leaf blade meet.

[0007]FIG. 4: Seedhead of “Ozarka” bermudagrass at full maturity.

[0008]FIG. 5. Cold tolerance of five bermudagrass varieties subjected to freezing temperatures ranging from −5 to −13° C. in a controlled chamber.

DETAILED DESCRIPTION OF THE VARIETY

[0009] Ozarka is similar to “Midland,” “Midland 99,” and “Tifton 44” in morphology and growth habit. Like Midland 99 and Tifton 44, “Ozarka” has relatively tall, upright growth in comparison to more decumbant cultivars such as “Greenfield.” The stem diameter, shoot length, and leaf widths of Ozarka, Midland, and Tifton 44 are similar. The leaves of “Ozarka” tend to be longer than those of Midland and Tifton 44. “Ozarka” typically produces inflorescences later and less profusely than Midland or Tifton 44. Like most hybrid bermudagrasses, “Ozarka” sets only a few seeds and therefore must be propagated vegetatively.

[0010] Ozarka has shown superior cold tolerance relative to previous bermudagrass varieties and has yielded well in the northern part of the bermudagrass belt. The superior adaptation, production and quality, for example, when grown in southern Missouri and Kansas thus make the variety unique among released bermudagrass varieties (FIG. 5). Based on its cold tolerance and stand persistence, “Ozarka” is widely adaptive north of Springfield, Mo. (37° 14′ N 93° 23′ W) extending to Elsberry, Mo. (39° 10′ N 90° 47′ W). This includes the southern one-third of Missouri and Kansas, and statewide in Oklahoma and Arkansas. Bermudagrass is generally not able to grow in the colder regions of the state, but “Ozarka” is highly tolerant to the differing cold temperature changes in the above listed region. A description of the variety is presented below.

[0011] A. Additional Characteristics of the Variety

[0012] Parentage: The variety is a clonally propagated F₁ hybrid of the cross of A9959×‘Coastal’. Oklahoma accession A9959 (PI 253302) is a cold tolerant clonal bermudagrass introduction from Yugoslavia. Coastal is the F₁ hybrid of ‘Tift’ bermudagrass and a plant introduction from South Africa.

[0013] Propagation: Vegetative (asexual) by means of propagating plant crowns, stolons and rhizomes.

[0014] Growth habit: Tall, upright, warm season perennial grass that spreads by rhizomes and stolons to form a dense sod. Rhizomes are found at a depth of greater than 4 cm, allowing rapid regrowth and recovery from sprig harvesting. Stolons and rhizomes branch from nodes.

[0015] Stem node diameter: mean=1.6 mm range=1.2 to 2.0 mm.

[0016] Internode diameter: mean=1.0 mm range=0.8 to 1.2 mm.

[0017] Internode length: mean=34.9 mm range=8 to 60 mm.

[0018] Mature leaf blade length: mean=99.2 mm range=56 to 158 mm.

[0019] Mature leaf blade width: mean=4 mm.

[0020] Other leaf blade characteristics: The variety has long leaves compared to other bermudagrass varieties. Leaves are glabrous on the abaxial and adaxial surfaces and taper toward the tip. Leaf characteristics vary slightly when under unusual fertility regimes.

[0021] Sheath: Open, shorter than the internode.

[0022] Ligule: A whitish fringe of hairs 1 mm in length.

[0023] Collar: Narrow and continuous.

[0024] Auricle: Absent.

[0025] Inflorescence: Produced less densely than most commercial bermudagrass varieties. When an inflorescence is produced, 4 to 6 digitate spikelets bear few, if any, viable seeds.

[0026] Plant color: The color designation of the variety is 7.5 GY 5/6 using a Munsell color chart rating.

[0027] Unmowed height: 75 to 100 cm.

[0028] Disease resistance: There have been no reports or observations of any unusual and/or severe insect or disease problems with the variety. Leaf disease has been minimal when other bermudagrass varieties showed severe infections.

[0029] Rooting: Produces vegetatively propagated roots from nodes of both stolons and rhizomes (nodal or adventitious roots), which are in the ground contact. The entire root system is comprised of adventitious roots that develop laterally and tend to become rudimentary unless the stolon or rhizome is severed. Once severed, the rudimentary roots rapidly develop to support the severed portion of the plant.

[0030] B. Growth Characteristics

[0031] Forage Yield for the variety has been evaluated in clipping trials at Mt. Vernon, Mo., (Southwest Missouri Research and Education Center; 37°06′ N 93°49′ W), Haskell (Eastern Research Station, 35°13′ N 95°08′ W), Chickasha (South Central Research Station, 35°03′ N 97°56′ W), and Ardmore (Noble Foundation, 34°10′ N 97°08′ W) Okla., Batesville, Ark., (Livestock and Forestry Branch Station, 35°46′ N 91°38′ W) and Parsons, Kans. (Southeast Agricultural Research Center 37°20′ N 95°15′ W).

[0032] In almost every yield trial conducted, “Ozarka” has yielded as much or more forage than other varieties. In a three-year trial at Mt. Vernon, Mo., “Ozarka” had an average yield of 9,867 kg ha⁻¹ (Table 1). In this trial, the three-year average yields of “Ozarka” were equal to those for Midland 99, but 13% greater than Tifton 44, 31% greater than ‘Hardie’ and 38% greater than ‘Guymon’. At Parsons, Kans., “Ozarka” had outstanding yields, producing an average 14,986 kg ha⁻¹ of forage per year (Table 2). Although the yields were less during the first year of this trial, by the third (and final) year it produced significantly (18 to 40%) more forage than other varieties tested.

[0033] At Batesville, Ark., “Ozarka” had a four-year average yield of 15,702 kg ha⁻¹. This yield from “Ozarka” was similar to Tifton 44 and ‘Greenfield’, but 14% greater than Midland, 24% greater than ‘World Feeder’ and 37% greater than Guymon (Table 3). In trials conducted at Haskell and Chickasha, Okla., the variety yielded similarly to Tifton 44, Hardie and Midland 99, but produced significantly more forage than Midland, ‘Quickstand’, World Feeder and Greenfield (Tables 4 and 5). Yield tests conducted at the Noble Foundation, near Ardmore, Okla. showed that the variety produced four-year average yields that were similar to Coastal, Hardie, and Midland 99, but yielded 19% more forage than Tifton 44, 22% more than Midland, and 47% more than Quickstand (Table 6).

[0034] The excellent production of “Ozarka” in Missouri, Kansas, Arkansas and Oklahoma is due in large part to its cold hardiness. In laboratory cold tolerance tests, “Ozarka” had a T_(mid) value of −9.0° C. (FIG. 5). This T_(mid) value was significantly lower (i.e. indicating more cold tolerance) than any other variety tested including Midland 99, Greenfield, Midland, and Tifton 44. T_(mid) values indicate the coldest temperature at which 50% of the plants survive.

[0035] The variety has survived well in a number of environments. Stands of the variety have not shown signs of winterkill at any location where yield testing has been conducted. Further, observation plots as far north as Elsberry, Mo. (39°10′ N 90°46′ W) have persisted more than six years where all other bermudagrass varieties showed signs of winterkill.

[0036] Overall the forage quality of “Ozarka” has been similar or better than other high-yielding bermudagrass varieties. At Mt. Vernon, “Ozarka” had acid detergent fiber (ADF), neutral detergent fiber (NDF) and crude protein (CP) values that were similar to Midland 99 and Tifton 44 (Table 7).

[0037] Forage quality of “Ozarka” was also tested during 1995 at both Chickasha and Haskell, Okla. At Chickasha, “Ozarka” had ADF, NDF and CP values that were equal to the highest yielding varieties in the trial (Tifton 44, Hardie and Midland 99) except that it had 10 g kg⁻¹ less ADF than Tifton 44 (Table 8). At Haskell, “Ozarka” has less ADF and NDF than the other high-yielding varieties (Midland 99, Hardie, and Tifton 44) (Table 9). The crude protein concentration of “Ozarka” was similar to all the other varieties tested at Haskell. TABLE 1 Annual and three-year average forage yield of five bermudagrass varieties grown at the Southwest Missouri Research and Education Center, near Mt. Vernon, Missouri 1996 1997 1998 Variety kg ha⁻¹ Average Ozarka 6,707 11,189 11,704 9,867 Midland 99 5,980 11,005 11,119 9,368 Tifton 44 5,615 10,219 9,931 8,588 Hardie 4,580 7,622 8,366 6,856 Guymon 4,116 7,233 7,048 6,132 Average 5,400 9,454 9,634 8,162 LSD (0.05) 1,244 1,059 1,532 992

[0038] TABLE 2 Annual and 3-year average yield of 6 bermudagrass varieties grown at the Mound Valley Unit, Southeast Agricultural Research Center, near Parsons, Kansas 1993 1994 1995 Variety kg ha⁻¹ Average Ozarka 10,304 18,144 16,509 14,986 Hardie 13,373 17,584 13,530 14,829 Tifton 44 11,715 15,792 12,970 13,492 Midland 9,856 13,171 10,886 11,305 Greenfield 10,170 9,587 10,774 10,177 World Feeder 9,206 9,632 9,946 9,595 Average 10,771 13,985 12,436 12,397 LSD (0.05) 1,322 1,770 1,837

[0039] TABLE 3 Annual and 4-year forage yield of 6 bermudagrass varieties grown at the Livestock and Forestry 1995 1996 1997 1998 Variety kg ha⁻¹ Average Tifton 44 18,637 13,530 1,837 18,122 16,442 Ozarka 18,144 13,104 13,709 17,853 15,702 Greenfield 18,637 11,962 14,224 14,448 14,818 Midland 16,755 9,050 13,619 14,470 13,474 World Feeder 15,501 7,706 12,768 11,917 11,973 Guymon 13,574 7,146 8,355 10,192 9,817 Average 16,875 10,416 13,026 14,500 13,704 LSD (0.05) 3,203 2,733 2,016 2,262 1,792

[0040] TABLE 4 Annual and 4-year average forage yield of 8 bermudagrass varieties grown at the South Central Research Station, near Chickasha, Oklahoma 1995 1996 1997 1998 Variety kg ha⁻¹ Average Tifton 44 26,006 25,446 21,213 20,093 23,190 Hardie 28,829 26,006 18,525 16,083 22,361 Ozarka 27,059 22,624 18,502 16,710 21,224 Midland 99 25,693 22,736 19,286 17,002 21,179 Midland 23,834 20,362 16,867 12,275 18,335 Quickstand 20,586 19,869 11,738 6,115 14,577 World Feeder 18,256 16,016 9,968 5,802 12,511 Greenfield 16,621 16,934 11,088 5,533 12,544 Average 23,360 21,249 15,898 12,452 18,240 LSD (0.05) 3,539 3,002 2,509 2,778 2,106

[0041] TABLE 5 Annual and 3-year average forage yield of 8 bermudagrass grown at the Eastern Research Station, near Haskell, Oklahoma 1995 1996 1997 Variety kg ha⁻¹ Average Midland 99 24,901 21,146 20,675 22,241 Hardie 23,811 18,973 21,347 21,377 Tifton 44 22,938 19,914 20,807 21,220 Ozarka 22,557 20,115 20,899 21,290 Midland 21,011 17,584 17,181 18,592 Quickstand 20,070 17,069 14,314 17,151 Greenfield 18,928 13,709 15,501 16,046 World Feeder 17,046 15,165 15,322 15,844 Average 21,408 17,959 18,256 19,208 LSD (0.05) 1,008 1,949 2,419 1,613

[0042] TABLE 6 Annual and 4-year average forage yield of 7 bermudagrass varieties grown at the Noble Foundation, near Ardmore, Oklahoma 1996 1997 1998 1999 Variety kg ha⁻¹ Average Coastal 5,750 7,056 13,526 10,619 9,238 Ozarka 7,195 5,812 12,491 10,927 9,106 Hardie 7,499 6,193 10,917 10,759 8,842 Midland 99 6,056 5,994 11,877 9,801 8,432 Tifton 44 5,811 5,363 9,826 8,652 7,413 Midland 6,154 4,239 9,178 8,679 7,062 Quickstand 4,416 1,960 6,642 6,324 4,835 Average 6,126 5,231 10,637 9,394 7,847 LSD (0.05) 1,570 1,698 2,272 1,430 1,578

[0043] TABLE 7 Three-year average (1996-1998) of acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude protein of 5 bermudagrass varieties grown at the Southwest Missouri Research and Education Center, near Mt. Vernon, Missouri Acid Detergent Neutral Detergent Fiber Fiber Variety g kg⁻¹ Crude Protein Guyman 262 553 192 Hardie 282 537 188 Tifton 44 271 589 178 Midland 99 270 573 177 Ozarka 271 575 177 Average 271 565 182 LSD (0.05) 6.1 19.0 7.3

[0044] TABLE 8 Acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude protein during 1995 of eight bermudagrass varieties grown at the South Central Research Station, near Chickasha, Oklahoma Acid Detergent Neutral Detergent Fiber Fiber Variety g kg⁻¹ Crude Protein Tifton 44 383 724 130 Hardie 376 711 129 Ozarka 373 703 128 Midland 99 369 714 126 Midland 374 713 130 Quickstand 366 704 119 World Feeder 359 714 121 Greenfield 360 683 128 Average 370 710 126 LSD (0.05) 9 20 NS

[0045] TABLE 9 Acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude protein during 1995 of eight bermudagrass varieties grown at the Eastern Research Station, near Haskell, Oklahoma Acid Detergent Neutral Detergent Fiber Fiber Variety g kg⁻¹ Crude Protein Midland 99 389 722 122 Hardie 395 731 112 Tifton 44 401 755 115 Ozarka 376 712 125 Midland 384 726 124 Quickstand 397 740 113 Greenfield 380 713 132 World Feeder 375 734 121 Average 389 730 120 LSD (0.05) 12 13 NS 

What is claimed is:
 1. The new and distinct hybrid bermudagrass variety “Ozarka” as illustrated and described herein. 